title: The association between sleep duration and obesity in older adults.
abstract: BACKGROUND
  Reduced sleep has been reported to predict obesity in children and young adults. However, studies based on self-report have been unable to identify an association in older populations. In this study, the cross-sectional associations between sleep duration measured objectively and measures of weight and body composition were assessed in two cohorts of older adults.
  
  
  METHODS
  Wrist actigraphy was performed for a mean (s.d.) of 5.2 (0.9) nights in 3055 men (age: 67-96 years) participating in the Osteoporotic Fractures in Men Study (MrOS) and 4.1 (0.8) nights in 3052 women (age: 70-99 years) participating in the Study of Osteoporotic Fractures (SOF). A subgroup of 2862 men and 455 women also underwent polysomnography to measure sleep apnea severity.
  
  
  RESULTS
  Compared to those sleeping an average of 7-8 h per night, and after adjusting for multiple risk factors and medical conditions, a sleep duration of less than 5 h was associated with a body mass index (BMI) that was on average 2.5 kg/m(2) (95% confidence interval (CI): 2.0-2.9) greater in men and 1.8 kg/m(2) (95% CI: 1.1-2.4) greater in women. The odds of obesity (BMI >or= 30 kg/m(2)) was 3.7-fold greater (95% CI: 2.7-5.0) in men and 2.3-fold greater in women (95% CI: 1.6-3.1) who slept less than 5 h. Short sleep was also associated with central body fat distribution and increased percent body fat. These associations persisted after adjusting for sleep apnea, insomnia and daytime sleepiness.
  
  
  CONCLUSIONS
  In older men and women, actigraphy-ascertained reduced sleep durations are strongly associated with greater adiposity.
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine and Center for Clinical Investigation, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, OH 44106, USA. srp20@case.edu
authors.forename: S R
authors.initials: SR
authors.lastname: Patel
authors.forename: T
authors.initials: T
authors.lastname: Blackwell
authors.forename: S
authors.initials: S
authors.lastname: Redline
authors.forename: S
authors.initials: S
authors.lastname: Ancoli-Israel
authors.forename: J A
authors.initials: JA
authors.lastname: Cauley
authors.forename: T A
authors.initials: TA
authors.lastname: Hillier
authors.forename: C E
authors.initials: CE
authors.lastname: Lewis
authors.forename: E S
authors.initials: ES
authors.lastname: Orwoll
authors.forename: M L
authors.initials: ML
authors.lastname: Stefanick
authors.forename: B C
authors.initials: BC
authors.lastname: Taylor
authors.forename: K
authors.initials: K
authors.lastname: Yaffe
authors.forename: K L
authors.initials: KL
authors.lastname: Stone
mesh_terms: D050154:Adiposity; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001835:Body Weight; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000209:etiology*; D017286:Polysomnography; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000150:complications*; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications*; D013997:Time Factors; D014481:United States; D055105:Waist Circumference